In my early teens, I had a daydream, based on the BBC radio's programme A Seat in the Circle (or somesuch promise of romance) where new cinema and stage shows were previewed for avid listeners like me. So when I was about to open in a new play at school, perhaps during the long walk from the bus to the dress rehearsal, I would fantasize that our play was important enough to have me interviewed by the BBC's entertainment correspondent. Pretending I was a famous actor, I would mumble a monologue of modest answers to non-existent questions, which baffled any passers-by, who could rightly have assumed I was a little loopy. Fifty years on, this forgotten memory returned last Monday, somewhere during the evening of the world premiere of Fellowship of the Ring at the Odeon Theatre, Leicester Square in the heart of London. Tolkien honoured, as Peter Jackson put it before the screening, in his own country first.

I was allowed 10 tickets for the premiere and party, two of them for my cousin's grandchildren Andrew (16 years old and hasn't read Tolkien) and his brother Robin (14, who has). We drove together in a Mercedes Saloon (tailed by my other friends in a people mover) - London has a paucity of limousines - and heard the fans before we saw them, in their thousands lining Leicester Square behind police barriers. "Just keep walking Ian, don't sign autographs, the press is inside the cinema" - the sort of instruction that should be ignored, especially when you have cousins to impress! Hearing one's name called out, no, screamed out, might lead others to think there are a lot of people around with nothing much to do on a cold winter evening. But this was my first chance to meet presumably the hardcore Tolkien-on-film fans, and anyway I had a childhood dream to live out for real.

Before we got there, a Gandalf lookalike was on parade. I wish I'd met him. By comparison, I was a wizard in mufti, my new brown tweed suit by John Varvatos, my hair dressed with cold cream that I had mistaken for gel in my home bathroom. Andrew, Robin and I waved a lot, signed posters, stills, books galore and wondered how much of it and how soon it might land up on Ebay, where a recent peddler of a signed photograph of Magneto, claimed that I rarely did such things. It's true that I don't send a signed pic every time I'm asked by e-mail but I'm as diligent in signing playbills outside the theatre as are Nathan Lane and Matthew Broderick across West 44th Street in The Producers. They do of course have many more to attend to than Helen Mirren and I do, but I have one grouch. Parking is permitted only on the south side of the street, by their St James' Theatre's stage door, where chauffeured Town Cars are purring. We northsiders at the Broadhurst must dodge limos, yellow cabs, garbage trucks and other jaywalkers on their way to Sardi's restaurant or the Times Square lights, where Jim, my driver, is legally waiting. But then, on really crowded nights when the tourist theatre district is belying the image of a New York still in recovery, there's often a friendly young cop who guides me over as if I were the President.

But last Monday I was invited to feel like a film star, going down the banks of blinding flashlights and the line of microphones and TV cameras, which I've done a few too many times before yet still can enjoy. I like the idea of being observed afar by someone in their early teens who is acting-struck as I was, listening to A Seat in the Circle. This time I was keen most of all to get out the word that the dedication and love which Peter Jackson evoked in us all, is evident in the performances of the actors. That was why there was a full turnout of the Fellowship, who had come "by land, sea and air to be in town tonight" - I quote the line which introduced In Town Tonight, the half hour of celebrity interviews, another BBC favorite in our house. My mother loved the radio and one of my earliest memories was her bathing me as she told me the plot of the previous night's episode of the Basil Radford and Naughton Wayne comic adventure serial on the Home Service.

I'm not sure if BBC radio was there last Monday but I saw BBC TV, Jonathan Ross's Cinema 2001, BBC World Service, bbc.com, alongside every commercial channel I've ever heard of in Europe and the United States and beyond. The next day it was Liv Tyler, the image of a beautiful woman in scarlet, who dominated the coloured pages of the British press. I got in with her and Elijah Wood on the front page of "The Independent," which instantly became my favourite broadsheet, till I read their rather sniffy review.

It was lovely to see Ngila Dickson (Costume Design), Peters Jackson (Director), King and Owen (hair and make-up design), Rick and Melissa Porris (Co-producer and Publicity), Claire Cooper (Publicity), Bob Shaye (CEO New Line Cinema), Mark Ordesky (Executive producer) and the New Line team, Fran Walsh (Writer), and her family. And the actors reunited. A merry band. I sound like Liz Smith. In the Odeon we were on the front row upstairs next to Christopher Lee and in front of Ian Holm. Afterwards neither of these eloquent men could easily articulate their reaction to seeing the film for the first time, which is what I was like when I saw it three weeks ago in a New York screening room. The Odeon screen is spacious and the film filled every square inch.

After the Balrog I left for some fresh air and a cigarette. There the fans were still waiting, entertained only by the repeating relay of Howard Shore's score. They were mostly in their 20's and younger. I know of one 40 year old who flew from the States just to stand outside the cinema, the occasion was so momentous for him. Momentous for me too, who made the same journey.

Tobacco Dock, only a mile from my home on the Thames, had been Middle-earthed by Dan and Chris Hennah and their team who executed the sets for the films. About ten areas under one roof were themed, each serving the appropriate food. I made for the vegetarian compound, which may have been Hobbiton but was catering to crowds of humans all talking about the film. There were free bars but no drunks - a well-heeled guest-list. Our party had a group dance. Jetlag began nagging at 2.30 when we all drove home for a cup of tea.

The press seem to be unanimously in love with the film, confirming my impression that the Tolkienites and the uninitiated can enjoy it equally. The only question is how old do you have to be not to be scared witless by the excitements of Fellowship of the Ring, as I was by the witch in The Wizard of Oz and the death of Bambi's mother the first time round. Well, it would depend on the child, but from my own experience, the witch and the death didn't stop me soon relishing Shakespeare's often violent plays. Tolkien's 11-year-old grandson loved it on Monday. He asked for my autograph and that was a sweet moment at the party.

I relish these days so much because I want Peter's film to be enjoyed by as many people as possible. If today's British press reaction is repeated in other countries, particularly in the United States, it's looking good.